Method of blow molding on thermoforming a plastic hardskin/softcore multilayer sheet material
US4810457A · kind A · utility
7Cited by
3References
11Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 28, 1987 |
| Grant date | Mar 7, 1989 |
| Priority date | — |
| Expiry date | Sep 28, 2007 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB32B2439/70
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A process is disclosed for thermoforming a sheet or billet comprised of at least one outer layer of polypropylene and at least one adjacent layer of a random copolymer of propylene and ethylene and, optionally, a barrier layer. The sheet or billet is thermoformed into rigid articles which do not significantly distort under retort conditions by forming the sheet or billet at a temperature below the sticky point of the polypropylene layer and above the sheet distortion temperature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.